Place the lentils in a medium saucepan and cover with 4 cups of water. Add the salt and bring to a simmer over medium-high heat. Reduce the heat to low and cook until the lentils are tender but still hold their shape, about 20 to 30 minutes.

Drain the lentils thoroughly in a fine-mesh strainer—any excess water will prevent the dressing from adhering properly. Transfer the warm lentils to a large bowl.

Combine the carrots, cumin, cinnamon, and cayenne in a microwave-safe bowl. Cover the bowl tightly and microwave until the carrots are tender but still crisp, about 2 to 4 minutes.

Whisk the lemon juice and olive oil together in a small bowl until the mixture is slightly thickened and emulsified.

Add the spiced carrots, cilantro, and dressing to the lentils. Toss gently to combine, being careful not to mash the lentils. Season with salt and black pepper to taste.

Serve warm or at room temperature, allowing the flavors to meld for a few minutes if time permits.